1. Field of the invention
The present invention relates, in general, to an automatic brightness control device for use in an image reproducing apparatus to display images and, in particular, to an automatic brightness control device for use in preventing the deterioration of image quality caused by the frequent image muting to delete unnecessary images on the screen.
2. Description of the prior art
Generally, the prior image reproducing apparatus effects image muting to delete unnecessary images on the screen. When image muting is effected in the prior arts, the screen of image reproducing apparatus is formed in a black level without regard to the brightness level achieved before image muting is effected. However, when image muting is effected frequently, screen brightness darkens in its entirety, thereby deteriorating the reproduced image quality.
Therefore, it is an object of the present invention to provide an automatic brightness control device for use as a part of the image reproducing apparatus to adjust the brightness level of image muting to the average brightness level achieved just before image muting is effected.
Further, it is an object of the present invention to provide an automatic brightness control device for use as a part of the image reproducing apparatus to obtain a stabilized brightness level by taking the average brightness level of the last picture plane just before the present image muting is started.
Also, it is an object of the present invention to provide an automatic brightness control device for use as a part of the image reproducing apparatus to obtain a bright and stable picture plane which admits of no deterioration.